In commercial restaurants, cooking grills and deep-fryer units have a hood for exhausting fumes. Fire suppression systems have conventionally been built into these hoods. These fire suppression systems include a nozzle in the hood, a source of a fire-retardant powder with a CO.sub.2 propellant spaced from the cooking unit and piping and a valve connecting the source of fire-retardant chemical with the nozzle. A fusible link or other heat-sensitive mechanism is provided in the hood to open the valve when a fire occurs. The powder is thus dispersed through the nozzle. The chemical may put the fire out but the powder is spread over a very large area and takes considerable time to clean up. The restaurant may be closed for several days during the clean-up procedure. Further, dense black smoke usually spreads throughout the restaurant, causing alarm, and also causing smoke damage. An example of a fire-retardant system of this nature is disclosed in the U.S. Pat. No. 3,407,879 to O'Rear (issued Oct. 29, 1968). An example of another fire protection system built into a hood is disclosed in the U.S. Pat. No. 3,773,111 to Dunn (issued Nov. 20, 1973).
A fire-extinguishing system for a home range is disclosed in the Freedman U.S. Pat. No. 3,209,837 (issued Oct. 5, 1965). In Freedman, a fire-extinguishing powder is rolled up in a sheet material within a hood above the range. The sheet material is maintained in a roll by a fusible link. Upon melting of the fusible link, the sheet unrolls, thereby depositing the fire-extinguishing powder onto the range.
Fire curtains adapted to drop between a ceiling and a floor are disclosed by Singer in U.S. Pat. No. 3,687,185 (issued Aug. 29, 1972) and by Hattori in U.S. Pat. No. 4,077,474 (issued Mar. 7, 1978). In Singer, a fire curtain drops from the ceiling to the floor upon actuation of an automatically activated fire-extinguisher system which utilizes gas pressure to disengage a latch for the curtain. The release system relies on a drop in the gas pressure of the system. In Hattori, a mixture of water and a bubbling agent in the form of fine bubbles flows down the curtain to keep the curtain cool. The curtain is discharged by release of a latch through an automatically operated hydraulic cylinder.